In urban environments, personal space sometimes disappears altogether, with urbanites actually pressing up against each other.

One solution is the Urban Porcupine fiber-fill jacket. The shell layer is a mesh or fairly open weave or knit. The inner layer has sharpened quills fastened to it with
the sharp ends directed outward. Normally, the quill tips reside below the outer layer, within the fill layer, and cannot be seen. If an urbanite presses against or attempts to grab the jacket wearer, the fill layer is compressed, and the quill tips penetrate the outer layer, as well as the skin of the urbanite.

As the urbanite recoils in pain, the fiber fill instantly recovers and the quill tips disappear beneath the surface. The offending urbanite is then left to ponder the mysterious stigmatic grid of red puncture wounds on his hands.

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Having been hugely successful with the Urban Porcupine Jacket, Back-Off Fashions now offers the Back-Off Bouffant. This is a thin helmet bristling with barbed quills. The tips of the quills invisibly reside below the surface of a big hair wig. If attacked, the wearer of the Bouffant is taught to head-butt the attacker. After this head butting, the stunned attacker staggers away with the wig covered helmet stuck fast to his abdomen, desperately trying to remove what he now believes must be a wild, hairy animal, eating into him...

Hm... I'd settle on just some gloves made of the stuff, but instead of contact you flare your hand and fingers out, stretching the material and sending the spikes flared out. Tip the spikes with lemon, vinegar and chilli and you're wielding a nasty, nasty weapon...

[Steve DeGroof] Yes, eventually this vest business will spiral into an arms race. As personal space becomes zealously defended, everyone will want long quills, then even longer quills. Great cities like New York will occasionally become paralyzed when masses of quill vested urbanites accidentally stick together at intersections, at rush hour, creating what newscasters will dub quill-lock.

Mr. President! We cannot allow a porcupine jacket gap! <overcome with emotion Dr. Pluterday lurches from her wheelchair, standing unsteadily, looking down at her feet with astonshment> "Mien Fuhrer, I CAN WALK !"